News Flash - Portable Toilets

Statewide Septic Service now has portable toilet rentals available!
Call us at 262-692-9742 for more information.
Reminder: Sheboygan County Maintenance for 3rd Quarter is Due December 6, 2019

The Septic System


The septic system is really a Wastewater Recycling System that utilizes the natural soil to treat the wastewater before returning it to the groundwater basin.


What happens when you flush the toilet?
Where does the wastewater go?
For those of you not connected to a municipal sewer, the solution lies in the septic tank.


septicsystempic1

A septic tank is typically the first component of a septic system.  A system can be as simple as a septic tank with a efficient filter screen and a drainfield or include any number of add-ons, such as an aeration tank, sand filter, pump/siphon chamber or sand mound.


No one should enter a septic or other treatment or holding tank for any reason without being in full compliance with OSHA standards for entering a confined space.  The atmosphere within the septic or other treatment of holding tank may contain lethal gases, and rescue of a person from the interior of the tank may be difficult or impossible.
septicsystempic2


A septic tank looks like the illustration above.  The size of the tank depends upon the number of bedrooms in teh house, not the number of people or plumbing fixtures.  The sized range from 750 gallons on up and may be configured as one or two septic tanks.  Having two septic tanks (or a two compartment septic tank) increases detention time of the waste water, which helps to further reduce the suspended solids that could flow into the drainfield.

The drainfield is the area where the liquid from the septic tank soaks into the ground.  The soil & micro-organisms remove viruses, bacteria, and most other contaminant's typically found in household wastewater.  The drainfield area may consist of one or more trenches, a rectangular bed or an above grade design like a mound (as discussed later).  One or more observation tubes are placed in the drainfield area to monitor the infiltrative surface.


When the effluent (the technical name for the treated liquid from the septic tank) has to be lifted uphill into a drainfield, another tank is installed after the septic tank.  This tank contains a pump with floating on and off switches to send the effluent into the drainfield at preset intervals.  This pump tank (also known as a pump chamber, dosing chamber or lift station) has a high water alarm float switch connected to an alarm to warn the user when the pump has failed to come on.

Since 1980, pump tanks have about a one-day's reserve capacity once the pump fails and the alarm sounds.  However, most septic system effluent pumps provide maintenance free service for many years.


The waste water entering the septic tank separates into 3 layers.
1:  Solid waste that settles to the bottom of the tank; (sludge)
2:  Grease, fat and floating solid materials which rise to the top of the tank; (scum)

3:  A partially clarified liquid zone; effluent.

The solid waste is food for anaerobic bacteria, which releases gas and liquid components.  The gas is dispersed through the plumbing system vents in the house and drainfield vents.  Solids do accumulate in the septic tank.  The tank must be serviced (pumped out) every 3 years or when ever the solid component of the tank exceeds 1/3 of the tank volume to reduce the chance of solid material flowing into the drainfield.

Grease and other floating solids are prevented from flowing out of the tank by a baffle, filter, or screen located on the inside of the tank at the outlet end.  Another baffle is placed on the inlet side of the septic tank.  This forces the incoming waste down into the tank, which prevents short-circuiting across the tank.  These baffles can deteriorate over time and must be checked at each tank servicing.  In theory, only liquid flows out of the septic tank and into the drainfield, thereby recycling the household waste water into the ground.  There are tank effluent filters available that can prevent larger suspended solids in the wastewater from getting out of the septic tank, which may clog pumps, distrubution pipes and soil.  These filters are commonly serviced with routine septic tank pumping.

Click to go back to Home

Outlet Filter-Screen


The outlet filter screen of the primary treatment tank should be cleaned as necessary to ensure proper operation.  The filter cartridge must not be removed unless provisions are made to retain solids in the tank that may slough off the filter when removed from its enclosure.  If the filter is equipped with an alarm, the filter should be serviced if/when the alarm is activated continuously.  Occasional short duration filter alarms may inidicate surge flows or an impending continous alarm.

Click to go back to Home

Soil Infiltration System

Soil Infiltration System (dispersal cell)

The drainfield (soil infiltration) is the final and most important step of the effluent treatment and dispersal.  The size, elevation, location and shape fo the drainfield are all relative to the expected usage and soil characteristics.

The drainfield sizing is determined by the flow from the house (based on number of bedrooms) and the type of soil.  Usually the more pervious the soil, teh smaller the drainfield, however, a certified soil tester makes this determination based on the many physical features within the soil, such as texture, structure, consistence and layering of the soil.  This information is recorded on a "Soil and Site Evaluation Report" form.

The elevation and location of the drainfield is determined by the soil characteristics and depth of limiting conditions such as seasonal water table, saturation zones with the soil, or bedrock.  For systems without pretreatment, it is necessary to maintain a safe vertical distance of 3 feet between the bottom of the drainfield and limiting conditions for proper treatment and renovation of effluent.

The shape of the drainfield is dependent upon the maximum length of suitable soil available, preferable along the contour.  A drainfield design using trenches or narrow beds has been shown to improve aeration in the soil beneath the gravel thereby enhancing system treatement performance and longevity.  When there are several trenches or beds, a distribution box may be incorporated to promote equal distribution of effluent.

Effluent inside the drainfield is dispersed in two ways - gravity or pressure distribution.  Pressure distribution uses small diameter pipes and relies on a pump to force the effluent into the piping network.  Research has shown that a pressure distribution network will effectively disperse the effluent throughout the drainfield evenly thereby delaying the over saturation of any one part of the drainfield.  Saturation promotes clogging of the infiltrative surface.  When a pressure distribution drainfield is lower in elevation than the septic tank, a siphon may be used to force the effluent through the system instead of a pump.  A siphon must be checked periodically to ensure that it is properly discharging effluent in doses rather than "trickling" effluent into the drainfield.

Figures 1-4 depict typical drainfield layouts that are currently used in Wisconsin.


1: Gravity
1Gravity

 


2: Pressure
2 Pressure

This type of system is used when the soil absorption bed is located higher in the landscape or where pressure distribution is desired.

3:  At Grade

3 At Grade


4:  Mound
4 Mound

This system is similar to the At-Grade with washed sand placed on the plowed surface and the drainfield bed constructed in the sand.  When finished, this will be approximately 3-4 ft above the grade.

Figures 5 & 6 depict advance pretreatment systems.


5:  Sand Filter
5 Sand

Sand filters, utilize a sand media within a containment structure. Wastewater is treated as it passes over bacteria attached films on the sand media. As with the ATU, these units produce a high quality effluent to the soil.

 

 

6:  Aerobic Treatment

6 Aerobic

This unit treats the effluent at the tank through aeration of the wastewater. This promotes the growth of bacteria that reduces wastewater constituents and produces a higher quality effluent to the soil absorption bed.

 

Note: Graphics supplied by the Department of Commerce

 

Click to go back to Home

Drainfield Life Span


There are circumstances that shorten the life of a drainfield.

1:  Hydraulic Overloading
This is a condition where soil beneath the drainfield becomes saturated resulting in ponding.
This condition can be cause by:


A:  Drainfield is undersized for the current usage
B:  Leaking plumbing fixtures
C:  Surface water into the system
D:  Surge loading (e.g. doing all the clothes washing on one day)
 Note that laundry should be spaced out.

2.  Grease
Excessive grease can congeal in the sewer line to the septic tank or inside the tank.
The septic tank may accumulate a layer of solid fat, which cannot be readily broken down by bacterial action.

Grease should be treated as garbage and kept out of the septic tank whenever possible.

3: Non-Biodegradable Products
These products are made of cellulose, plastic or other non-biodegradable components.
They may plug the sewer lines, baffles and drainfield perforations or lodge in the pump. 

Here are some examples:
Sanitary Napkins,  Condoms,  Cotton Swabs,  Dental Floss,  Tampons,  Handwipes,  Infant Wipes,  Disposable Diapers and Cigarette Filters.

4: Chemicals That Kill Septic Tank Bacteria
When disposed of through the septic system, these chemicals may kill septic tank bacteria.
This can result in a severe decline in decomposition of the septic tank solids. 
It can take several weeks for the bacteria in the septic tank to re-establish.

Here are some examples:
Antibiotics, Other Medicines, Disinfectants, Painting Products, Gasoline, Oil, Degreasers and Pesticides.

5:  Clear Water Discharges
Building foundation drains, humidifier, and water softener discharges are considered clear water, which may be disposed into the ground separate from the septic system.  However, discharge from the softener during the recharge cycle is a salt brine which, in excessive amounts, could have an adverse affect on septic tank bacteria.

6:  Surface Drainage
Roof downspouts, driveway runoff and road ditches should be directed away from the septic system. 
The finished grade over the septic system should divert surface drainage of water away from the tanks and drainfield.

Click to go back to Home

Glossary & Terms


The glossary will be updated as we are asked about specific words (terms) used when communicating with our customers.

For commonly asked questions, please see the FAQ section under the Main Menu.


Click to go back to Home